1 //! An "interner" is a data structure that associates values with usize tags and
2 //! allows bidirectional lookup; i.e., given a value, one can easily find the
3 //! type, and vice versa.
5 use arena::DroplessArena;
6 use rustc_data_structures::fx::FxHashMap;
7 use rustc_data_structures::indexed_vec::Idx;
8 use rustc_data_structures::newtype_index;
9 use rustc_macros::symbols;
10 use serialize::{Decodable, Decoder, Encodable, Encoder};
14 use std::cmp::{PartialEq, Ordering, PartialOrd, Ord};
15 use std::hash::{Hash, Hasher};
17 use crate::hygiene::SyntaxContext;
18 use crate::{Span, DUMMY_SP, GLOBALS};
21 // After modifying this list adjust `is_special`, `is_used_keyword`/`is_unused_keyword`,
22 // this should be rarely necessary though if the keywords are kept in alphabetic order.
24 // Special reserved identifiers used internally for elided lifetimes,
25 // unnamed method parameters, crate root module, error recovery etc.
28 DollarCrate: "$crate",
31 // Keywords that are used in stable Rust.
68 // Keywords that are used in unstable Rust or reserved for future use.
82 // Edition-specific keywords that are used in stable Rust.
83 Dyn: "dyn", // >= 2018 Edition only
85 // Edition-specific keywords that are used in unstable Rust or reserved for future use.
86 Async: "async", // >= 2018 Edition only
87 Await: "await", // >= 2018 Edition only
88 Try: "try", // >= 2018 Edition only
90 // Special lifetime names
91 UnderscoreLifetime: "'_",
92 StaticLifetime: "'static",
94 // Weak keywords, have special meaning only in specific contexts.
98 Existential: "existential",
102 // Symbols that can be referred to with syntax_pos::sym::*. The symbol is
103 // the stringified identifier unless otherwise specified (e.g.
104 // `proc_dash_macro` represents "proc-macro").
106 aarch64_target_feature,
109 abi_msp430_interrupt,
117 advanced_slice_patterns,
129 allow_internal_unsafe,
130 allow_internal_unstable,
131 allow_internal_unstable_backcompat_hack,
134 arbitrary_self_types,
138 associated_type_defaults,
144 augmented_assignments,
145 automatically_derived,
146 avx512_target_feature,
149 bind_by_move_pattern_guards,
151 borrowck_graphviz_postflow,
152 borrowck_graphviz_preflow,
155 braced_empty_structs,
162 cfg_target_has_atomic,
163 cfg_target_thread_local,
168 closure_to_fn_coercion,
169 cmpxchg16b_target_feature,
174 conservative_impl_trait,
176 const_compare_raw_pointers,
184 const_raw_ptr_to_usize_cast,
195 crate_visibility_modifier,
198 custom_inner_attributes,
199 custom_test_frameworks,
202 default_lib_allocator,
203 default_type_parameter_fallback,
214 document_private_items,
215 dotdoteq_in_patterns,
216 dotdot_in_tuple_patterns,
217 double_braced_crate: "{{crate}}",
218 double_braced_impl: "{{impl}}",
219 double_braced_misc: "{{misc}}",
220 double_braced_closure: "{{closure}}",
221 double_braced_constructor: "{{constructor}}",
222 double_braced_constant: "{{constant}}",
223 double_braced_opaque: "{{opaque}}",
225 dropck_parametricity,
235 exclusive_range_pattern,
236 exhaustive_integer_patterns,
241 extern_absolute_paths,
243 extern_crate_item_prelude,
251 field_init_shorthand,
266 generic_associated_types,
271 hexagon_target_feature,
273 homogeneous_aggregate,
287 if_while_or_patterns,
289 impl_header_lifetime_elision,
290 impl_trait_in_bindings,
294 inclusive_range_syntax,
295 infer_outlives_requirements,
296 infer_static_outlives_requirements,
303 irrefutable_let_patterns,
306 issue_5723_bootstrap,
307 issue_tracker_base_url,
322 link_llvm_intrinsics,
329 macro_at_most_once_rep,
332 macro_lifetime_matcher,
333 macro_literal_matcher,
344 match_beginning_vert,
345 match_default_bindings,
355 movbe_target_feature,
388 omit_gdb_pretty_printer_section,
395 optin_builtin_traits,
400 overlapping_marker_traits,
404 panic_implementation,
418 poll_with_tls_context,
419 powerpc_target_feature,
420 precise_pointer_size_matching,
424 proc_dash_macro: "proc-macro",
426 proc_macro_attribute,
432 proc_macro_non_items,
433 proc_macro_path_invoc,
437 quad_precision_float,
450 reexport_test_harness_main,
460 re_rebalance_coherence,
470 rustc_allocator_nounwind,
471 rustc_allow_const_fn_ptr,
472 rustc_args_required_const,
475 rustc_const_unstable,
476 rustc_conversion_suggestion,
477 rustc_copy_clone_marker,
480 rustc_diagnostic_macros,
482 rustc_doc_only_macro,
483 rustc_dump_env_program_clauses,
484 rustc_dump_program_clauses,
485 rustc_dump_user_substs,
487 rustc_expected_cgu_reuse,
488 rustc_if_this_changed,
489 rustc_inherit_overflow_checks,
491 rustc_layout_scalar_valid_range_end,
492 rustc_layout_scalar_valid_range_start,
494 rustc_object_lifetime_default,
495 rustc_on_unimplemented,
498 rustc_partition_codegened,
499 rustc_partition_reused,
501 rustc_peek_definite_init,
502 rustc_peek_maybe_init,
503 rustc_peek_maybe_uninit,
505 rustc_proc_macro_decls,
509 rustc_std_internal_symbol,
513 rustc_then_this_would_need,
514 rustc_transparent_macro,
518 rust_eh_unwind_resume,
520 __rust_unstable_column,
521 rvalue_static_promotion,
537 sse4a_target_feature,
547 stmt_expr_attributes,
549 struct_field_attributes,
560 termination_trait_test,
563 test_accepted_feature,
564 test_removed_feature,
579 type_alias_enum_variants,
589 underscore_const_names,
591 underscore_lifetimes,
593 universal_impl_trait,
596 unrestricted_attribute_tokens,
597 unsafe_destructor_blind_to_params,
600 unsized_tuple_coercion,
612 visible_private_types,
615 warn_directory_ownership,
625 #[derive(Copy, Clone, Eq)]
633 /// Constructs a new identifier from a symbol and a span.
634 pub const fn new(name: Symbol, span: Span) -> Ident {
638 /// Constructs a new identifier with an empty syntax context.
640 pub const fn with_empty_ctxt(name: Symbol) -> Ident {
641 Ident::new(name, DUMMY_SP)
644 /// Maps an interned string to an identifier with an empty syntax context.
645 pub fn from_interned_str(string: InternedString) -> Ident {
646 Ident::with_empty_ctxt(string.as_symbol())
649 /// Maps a string to an identifier with an empty span.
650 pub fn from_str(string: &str) -> Ident {
651 Ident::with_empty_ctxt(Symbol::intern(string))
654 /// Maps a string and a span to an identifier.
655 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
656 Ident::new(Symbol::intern(string), span)
659 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
660 pub fn with_span_pos(self, span: Span) -> Ident {
661 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
664 pub fn without_first_quote(self) -> Ident {
665 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
668 /// "Normalize" ident for use in comparisons using "item hygiene".
669 /// Identifiers with same string value become same if they came from the same "modern" macro
670 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
671 /// different "modern" macros.
672 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
673 pub fn modern(self) -> Ident {
674 Ident::new(self.name, self.span.modern())
677 /// "Normalize" ident for use in comparisons using "local variable hygiene".
678 /// Identifiers with same string value become same if they came from the same non-transparent
679 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
680 /// non-transparent macros.
681 /// Technically, this operation strips all transparent marks from ident's syntactic context.
682 pub fn modern_and_legacy(self) -> Ident {
683 Ident::new(self.name, self.span.modern_and_legacy())
686 /// Transforms an identifier into one with the same name, but gensymed.
687 pub fn gensym(self) -> Ident {
688 let name = with_interner(|interner| interner.gensymed(self.name));
689 Ident::new(name, self.span)
692 /// Transforms an underscore identifier into one with the same name, but
693 /// gensymed. Leaves non-underscore identifiers unchanged.
694 pub fn gensym_if_underscore(self) -> Ident {
695 if self.name == keywords::Underscore.name() { self.gensym() } else { self }
698 // WARNING: this function is deprecated and will be removed in the future.
699 pub fn is_gensymed(self) -> bool {
700 with_interner(|interner| interner.is_gensymed(self.name))
703 pub fn as_str(self) -> LocalInternedString {
707 pub fn as_interned_str(self) -> InternedString {
708 self.name.as_interned_str()
712 impl PartialEq for Ident {
713 fn eq(&self, rhs: &Self) -> bool {
714 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
718 impl Hash for Ident {
719 fn hash<H: Hasher>(&self, state: &mut H) {
720 self.name.hash(state);
721 self.span.ctxt().hash(state);
725 impl fmt::Debug for Ident {
726 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
727 write!(f, "{}{:?}", self.name, self.span.ctxt())
731 impl fmt::Display for Ident {
732 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
733 fmt::Display::fmt(&self.name, f)
737 impl Encodable for Ident {
738 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
739 if self.span.ctxt().modern() == SyntaxContext::empty() {
740 s.emit_str(&self.as_str())
741 } else { // FIXME(jseyfried): intercrate hygiene
742 let mut string = "#".to_owned();
743 string.push_str(&self.as_str());
749 impl Decodable for Ident {
750 fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
751 let string = d.read_str()?;
752 Ok(if !string.starts_with('#') {
753 Ident::from_str(&string)
754 } else { // FIXME(jseyfried): intercrate hygiene
755 Ident::from_str(&string[1..]).gensym()
760 /// A symbol is an interned or gensymed string. A gensym is a symbol that is
761 /// never equal to any other symbol.
763 /// Conceptually, a gensym can be thought of as a normal symbol with an
764 /// invisible unique suffix. Gensyms are useful when creating new identifiers
765 /// that must not match any existing identifiers, e.g. during macro expansion
766 /// and syntax desugaring. Because gensyms should always be identifiers, all
767 /// gensym operations are on `Ident` rather than `Symbol`. (Indeed, in the
768 /// future the gensym-ness may be moved from `Symbol` to hygiene data.)
772 /// assert_eq!(Ident::from_str("x"), Ident::from_str("x"))
773 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x"))
774 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x").gensym())
776 /// Internally, a symbol is implemented as an index, and all operations
777 /// (including hashing, equality, and ordering) operate on that index. The use
778 /// of `newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
779 /// because `newtype_index!` reserves the last 256 values for tagging purposes.
781 /// Note that `Symbol` cannot directly be a `newtype_index!` because it
782 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
783 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
784 pub struct Symbol(SymbolIndex);
787 pub struct SymbolIndex { .. }
791 const fn new(n: u32) -> Self {
792 Symbol(SymbolIndex::from_u32_const(n))
795 /// Maps a string to its interned representation.
796 pub fn intern(string: &str) -> Self {
797 with_interner(|interner| interner.intern(string))
800 pub fn as_str(self) -> LocalInternedString {
801 with_interner(|interner| unsafe {
802 LocalInternedString {
803 string: std::mem::transmute::<&str, &str>(interner.get(self))
808 pub fn as_interned_str(self) -> InternedString {
809 with_interner(|interner| InternedString {
810 symbol: interner.interned(self)
814 pub fn as_u32(self) -> u32 {
819 impl fmt::Debug for Symbol {
820 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
821 let is_gensymed = with_interner(|interner| interner.is_gensymed(*self));
823 write!(f, "{}({:?})", self, self.0)
825 write!(f, "{}", self)
830 impl fmt::Display for Symbol {
831 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
832 fmt::Display::fmt(&self.as_str(), f)
836 impl Encodable for Symbol {
837 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
838 s.emit_str(&self.as_str())
842 impl Decodable for Symbol {
843 fn decode<D: Decoder>(d: &mut D) -> Result<Symbol, D::Error> {
844 Ok(Symbol::intern(&d.read_str()?))
848 // The `&'static str`s in this type actually point into the arena.
850 // Note that normal symbols are indexed upward from 0, and gensyms are indexed
851 // downward from SymbolIndex::MAX_AS_U32.
853 pub struct Interner {
854 arena: DroplessArena,
855 names: FxHashMap<&'static str, Symbol>,
856 strings: Vec<&'static str>,
857 gensyms: Vec<Symbol>,
861 fn prefill(init: &[&str]) -> Self {
862 let mut this = Interner::default();
863 this.names.reserve(init.len());
864 this.strings.reserve(init.len());
866 // We can't allocate empty strings in the arena, so handle this here.
867 assert!(keywords::Invalid.name().as_u32() == 0 && init[0].is_empty());
868 this.names.insert("", keywords::Invalid.name());
869 this.strings.push("");
871 for string in &init[1..] {
877 pub fn intern(&mut self, string: &str) -> Symbol {
878 if let Some(&name) = self.names.get(string) {
882 let name = Symbol::new(self.strings.len() as u32);
884 // `from_utf8_unchecked` is safe since we just allocated a `&str` which is known to be
886 let string: &str = unsafe {
887 str::from_utf8_unchecked(self.arena.alloc_slice(string.as_bytes()))
889 // It is safe to extend the arena allocation to `'static` because we only access
890 // these while the arena is still alive.
891 let string: &'static str = unsafe {
892 &*(string as *const str)
894 self.strings.push(string);
895 self.names.insert(string, name);
899 fn interned(&self, symbol: Symbol) -> Symbol {
900 if (symbol.0.as_usize()) < self.strings.len() {
903 self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize]
907 fn gensymed(&mut self, symbol: Symbol) -> Symbol {
908 self.gensyms.push(symbol);
909 Symbol::new(SymbolIndex::MAX_AS_U32 - self.gensyms.len() as u32 + 1)
912 fn is_gensymed(&mut self, symbol: Symbol) -> bool {
913 symbol.0.as_usize() >= self.strings.len()
916 // Get the symbol as a string. `Symbol::as_str()` should be used in
917 // preference to this function.
918 pub fn get(&self, symbol: Symbol) -> &str {
919 match self.strings.get(symbol.0.as_usize()) {
920 Some(string) => string,
922 let symbol = self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize];
923 self.strings[symbol.0.as_usize()]
930 use super::{Symbol, Ident};
932 #[derive(Clone, Copy, PartialEq, Eq)]
939 pub fn ident(self) -> Ident {
944 pub fn name(self) -> Symbol {
952 // This module has a very short name because it's used a lot.
959 fn is_used_keyword_2018(self) -> bool {
960 self == keywords::Dyn.name()
963 fn is_unused_keyword_2018(self) -> bool {
964 self >= keywords::Async.name() && self <= keywords::Try.name()
969 // Returns `true` for reserved identifiers used internally for elided lifetimes,
970 // unnamed method parameters, crate root module, error recovery etc.
971 pub fn is_special(self) -> bool {
972 self.name <= keywords::Underscore.name()
975 /// Returns `true` if the token is a keyword used in the language.
976 pub fn is_used_keyword(self) -> bool {
977 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
978 self.name >= keywords::As.name() && self.name <= keywords::While.name() ||
979 self.name.is_used_keyword_2018() && self.span.rust_2018()
982 /// Returns `true` if the token is a keyword reserved for possible future use.
983 pub fn is_unused_keyword(self) -> bool {
984 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
985 self.name >= keywords::Abstract.name() && self.name <= keywords::Yield.name() ||
986 self.name.is_unused_keyword_2018() && self.span.rust_2018()
989 /// Returns `true` if the token is either a special identifier or a keyword.
990 pub fn is_reserved(self) -> bool {
991 self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
994 /// A keyword or reserved identifier that can be used as a path segment.
995 pub fn is_path_segment_keyword(self) -> bool {
996 self.name == keywords::Super.name() ||
997 self.name == keywords::SelfLower.name() ||
998 self.name == keywords::SelfUpper.name() ||
999 self.name == keywords::Crate.name() ||
1000 self.name == keywords::PathRoot.name() ||
1001 self.name == keywords::DollarCrate.name()
1004 /// This identifier can be a raw identifier.
1005 pub fn can_be_raw(self) -> bool {
1006 self.name != keywords::Invalid.name() && self.name != keywords::Underscore.name() &&
1007 !self.is_path_segment_keyword()
1010 /// We see this identifier in a normal identifier position, like variable name or a type.
1011 /// How was it written originally? Did it use the raw form? Let's try to guess.
1012 pub fn is_raw_guess(self) -> bool {
1013 self.can_be_raw() && self.is_reserved()
1017 // If an interner exists, return it. Otherwise, prepare a fresh one.
1019 fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
1020 GLOBALS.with(|globals| f(&mut *globals.symbol_interner.lock()))
1023 /// An alternative to `Symbol` and `InternedString`, useful when the chars
1024 /// within the symbol need to be accessed. It is best used for temporary
1027 /// Because the interner outlives any thread which uses this type, we can
1028 /// safely treat `string` which points to interner data, as an immortal string,
1029 /// as long as this type never crosses between threads.
1031 // FIXME: ensure that the interner outlives any thread which uses
1032 // `LocalInternedString`, by creating a new thread right after constructing the
1034 #[derive(Clone, Copy, Hash, PartialOrd, Eq, Ord)]
1035 pub struct LocalInternedString {
1036 string: &'static str,
1039 impl LocalInternedString {
1040 pub fn as_interned_str(self) -> InternedString {
1042 symbol: Symbol::intern(self.string)
1046 pub fn get(&self) -> &str {
1047 // This returns a valid string since we ensure that `self` outlives the interner
1048 // by creating the interner on a thread which outlives threads which can access it.
1049 // This type cannot move to a thread which outlives the interner since it does
1050 // not implement Send.
1055 impl<U: ?Sized> std::convert::AsRef<U> for LocalInternedString
1057 str: std::convert::AsRef<U>
1059 fn as_ref(&self) -> &U {
1060 self.string.as_ref()
1064 impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for LocalInternedString {
1065 fn eq(&self, other: &T) -> bool {
1066 self.string == other.deref()
1070 impl std::cmp::PartialEq<LocalInternedString> for str {
1071 fn eq(&self, other: &LocalInternedString) -> bool {
1072 self == other.string
1076 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a str {
1077 fn eq(&self, other: &LocalInternedString) -> bool {
1078 *self == other.string
1082 impl std::cmp::PartialEq<LocalInternedString> for String {
1083 fn eq(&self, other: &LocalInternedString) -> bool {
1084 self == other.string
1088 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a String {
1089 fn eq(&self, other: &LocalInternedString) -> bool {
1090 *self == other.string
1094 impl !Send for LocalInternedString {}
1095 impl !Sync for LocalInternedString {}
1097 impl std::ops::Deref for LocalInternedString {
1099 fn deref(&self) -> &str { self.string }
1102 impl fmt::Debug for LocalInternedString {
1103 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1104 fmt::Debug::fmt(self.string, f)
1108 impl fmt::Display for LocalInternedString {
1109 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1110 fmt::Display::fmt(self.string, f)
1114 impl Decodable for LocalInternedString {
1115 fn decode<D: Decoder>(d: &mut D) -> Result<LocalInternedString, D::Error> {
1116 Ok(Symbol::intern(&d.read_str()?).as_str())
1120 impl Encodable for LocalInternedString {
1121 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1122 s.emit_str(self.string)
1126 /// An alternative to `Symbol` that is focused on string contents. It has two
1127 /// main differences to `Symbol`.
1129 /// First, its implementations of `Hash`, `PartialOrd` and `Ord` work with the
1130 /// string chars rather than the symbol integer. This is useful when hash
1131 /// stability is required across compile sessions, or a guaranteed sort
1132 /// ordering is required.
1134 /// Second, gensym-ness is irrelevant. E.g.:
1136 /// assert_ne!(Symbol::gensym("x"), Symbol::gensym("x"))
1137 /// assert_eq!(Symbol::gensym("x").as_interned_str(), Symbol::gensym("x").as_interned_str())
1139 #[derive(Clone, Copy, Eq)]
1140 pub struct InternedString {
1144 impl InternedString {
1145 pub fn with<F: FnOnce(&str) -> R, R>(self, f: F) -> R {
1146 let str = with_interner(|interner| {
1147 interner.get(self.symbol) as *const str
1149 // This is safe because the interner keeps string alive until it is dropped.
1150 // We can access it because we know the interner is still alive since we use a
1151 // scoped thread local to access it, and it was alive at the beginning of this scope
1155 fn with2<F: FnOnce(&str, &str) -> R, R>(self, other: &InternedString, f: F) -> R {
1156 let (self_str, other_str) = with_interner(|interner| {
1157 (interner.get(self.symbol) as *const str,
1158 interner.get(other.symbol) as *const str)
1160 // This is safe for the same reason that `with` is safe.
1161 unsafe { f(&*self_str, &*other_str) }
1164 pub fn as_symbol(self) -> Symbol {
1168 pub fn as_str(self) -> LocalInternedString {
1169 self.symbol.as_str()
1173 impl Hash for InternedString {
1174 fn hash<H: Hasher>(&self, state: &mut H) {
1175 self.with(|str| str.hash(state))
1179 impl PartialOrd<InternedString> for InternedString {
1180 fn partial_cmp(&self, other: &InternedString) -> Option<Ordering> {
1181 if self.symbol == other.symbol {
1182 return Some(Ordering::Equal);
1184 self.with2(other, |self_str, other_str| self_str.partial_cmp(other_str))
1188 impl Ord for InternedString {
1189 fn cmp(&self, other: &InternedString) -> Ordering {
1190 if self.symbol == other.symbol {
1191 return Ordering::Equal;
1193 self.with2(other, |self_str, other_str| self_str.cmp(other_str))
1197 impl<T: std::ops::Deref<Target = str>> PartialEq<T> for InternedString {
1198 fn eq(&self, other: &T) -> bool {
1199 self.with(|string| string == other.deref())
1203 impl PartialEq<InternedString> for InternedString {
1204 fn eq(&self, other: &InternedString) -> bool {
1205 self.symbol == other.symbol
1209 impl PartialEq<InternedString> for str {
1210 fn eq(&self, other: &InternedString) -> bool {
1211 other.with(|string| self == string)
1215 impl<'a> PartialEq<InternedString> for &'a str {
1216 fn eq(&self, other: &InternedString) -> bool {
1217 other.with(|string| *self == string)
1221 impl PartialEq<InternedString> for String {
1222 fn eq(&self, other: &InternedString) -> bool {
1223 other.with(|string| self == string)
1227 impl<'a> PartialEq<InternedString> for &'a String {
1228 fn eq(&self, other: &InternedString) -> bool {
1229 other.with(|string| *self == string)
1233 impl fmt::Debug for InternedString {
1234 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1235 self.with(|str| fmt::Debug::fmt(&str, f))
1239 impl fmt::Display for InternedString {
1240 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1241 self.with(|str| fmt::Display::fmt(&str, f))
1245 impl Decodable for InternedString {
1246 fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
1247 Ok(Symbol::intern(&d.read_str()?).as_interned_str())
1251 impl Encodable for InternedString {
1252 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1253 self.with(|string| s.emit_str(string))
1263 fn interner_tests() {
1264 let mut i: Interner = Interner::default();
1265 // first one is zero:
1266 assert_eq!(i.intern("dog"), Symbol::new(0));
1267 // re-use gets the same entry:
1268 assert_eq!(i.intern("dog"), Symbol::new(0));
1269 // different string gets a different #:
1270 assert_eq!(i.intern("cat"), Symbol::new(1));
1271 assert_eq!(i.intern("cat"), Symbol::new(1));
1272 // dog is still at zero
1273 assert_eq!(i.intern("dog"), Symbol::new(0));
1274 let z = i.intern("zebra");
1275 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32));
1276 // gensym of same string gets new number:
1277 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32 - 1));
1278 // gensym of *existing* string gets new number:
1279 let d = i.intern("dog");
1280 assert_eq!(i.gensymed(d), Symbol::new(SymbolIndex::MAX_AS_U32 - 2));
1284 fn without_first_quote_test() {
1285 GLOBALS.set(&Globals::new(), || {
1286 let i = Ident::from_str("'break");
1287 assert_eq!(i.without_first_quote().name, keywords::Break.name());